VAI-28 Is a multi-purpose two-engined turboprop amphibian would carry up to 8 passengers or freights transportation, search and rescue missions, patrol, travel, sightseeing flights etc.
The main feature of the project is high performances with amphibious properties, i.e. a capability to perform take-off and landing from water surface, from artificial runways, and also from a ground. Water-to-coast coming capability (and on the contrary) is provided under suitable conditions of the coastal slope.
Thus, this airplane allows to have high mobility on range, and whenever possible deployment on a river, lake, sea, airfields, off-aerodrome areas with suitable conditions.
The VAI-28 is of conventional high-wing utility design with a T-tail and single-step fuselage boat, and engines layout on the wing above.
The power unit consist of two turboprop engines PT6-21 manufactured in Canada. High specific performances allow to have acceptable efficiency and range. Engine power with a good aerodynamics allows to continue flight by one engine if the second engine failed.The upper engines arrangement minimises water splashes hit and a dust hit. Tractor propellers provide the wing and flaps blowing, it is in addition increases lift on take-off and landing. For negative pitching moment reduction on take-off propeller axis are turned on 5 degrees upwards.
In the base version the amphibian has spacious comfortable interior on 8 places, the cabin height allows to standing up straight. Passenger seats are regulated, seat pitch allows to take place with convenience for the passenger above medium-sized. For the passengers and crew entrance there are a two doors in the fuselage aft on both sides, and we have a special ladder retracted when the door is closing. In the cockpit and passenger cabin there are emergency hatches for escape, they also can be used for ventilation. Behind the passenger cabin there is a lavatory. The airplane is equipped by central air conditioner. The airplane crew is 1-2 pilots takes place in the cockpit with the good review and modern avionics. There are two luggage compartments in the fuselage nose and aft . Also in aft compartment we have an inflatable boat or a liferaft.
The wing and the fuselage are have special cavities filled with foam intended to hold afloat in case of damage. For casually got water extraction from the boat fuselage there is a special pump.
The internal volume of the amphibian fuselage has four sealed compartments, each has the sealed hatch. At case of any compartment damage sealed doors are closed and an amphibian remains afloat.
The main material of the airplane structure is carbon composite, in small amounts also are applied fiberglass and an aramid fibre composites. It gives the chance to make units of the airframe with small weight, but with high strength and rigidity, to receive the smooth external surface, corrosion firmness. Some units of the airplane, such as a landing gear, control, an engine mount, etc. are traditionally are made of aluminium and titanium alloys, and steel. All parts subject to corrosion are made of corrosion-proof materials or have effective anticorrosive cover.
The amphibian fuselage has boat configuration, it has a single-step bottom. The boat nose shape is chosen proceeding from conditions of aerodynamics, the review for the crew, seaworthiness. Bottom dimensions and angles are determined proceeding from seaworthiness, forces transfer to airframe, layout. The boat fuselage has a flat zone between the cockpit and step, it offers some advantages on a slipping mode and simplifies a design. The fuselage main frame includes transverse members (frames), edgings of cut-outs and hatches, bilge beams and keel beam, a stressed skin.
The wing is integral, one-piece, two-spar layout. It has GAW-2 aerofoil section and also the high aspect ratio that provides high flight performances. The carbon composite allows to make such narrow and long wing with small weight and high strength. We have an integrated fuel tanks in the wing, disposed between the spars. Underneath the wing in a tip zone are mounted transversal stability floats. In the wing root are disposed single-slotted flaps, close to tip are disposed ailerons. At the wing tips are disposed winglets, they improve aerodynamics.
The tail unit has a T-shape layout. This increase its efficiency. Stabilizer, fin, elevators and rudder have a spars and stressed-skin structure.
The control system is mechanical, unpowered, has the combined harness. Control surfaces and ailerons have overhang balance and are supplied by trim tabs with the electric drive. The airplane can be equiped by autopilot .
The landing gear has a three-legs layout with a tailwheel. Such layout improves passableness at coming from water to coast, at taxiing on irregularities at unpaved airfields and platforms, and also has smaller weight and cost. Telescopic shock-absorbers with the big course promote passableness improvement on a ground and energy damping on landing. Landing gear is retract to the fuselage compartment. The tailwheel is self-oriented with the locking gear, at retracted position is located in the tail compartment.
Weight and Volume
|Take-off weight||4632 kg||10202 lbs|
|Standard useful load||1000 kg||2200 lbs|
|Empty weight||2100 kg||4625 lbs|
|Fuel weight||1532kg||3375 lbs|
|Wing Span||19.23 m||63.05 tf|
|Wing area||27.24 m2||293 ft2|
|Wing loading||170 kg/m2||35 lb/ft2|
|Length||15.18 m||49 ft|
|Height||4.75 m||15.0 ft|
|Cabin height||1.85 m||6.07 ft|
|Cabin width||1.6 m||5.25 ft|
|Cabin length||3.5 m||11.5 ft|
|Total volume||2 m3||70 ft3|
|Crew||1 or 2 pilots|
|Maximum speed||380 km/h||205 kts|
|Cruise speed||320 – 350 km/h||170 - 190 kts|
|Range||3300 km||2050 mi, 1800 nm|
|Optimal altitude||3500 – 4500 m||11500 – 14500 ft|
|Runway length||500 m||1600 ft|
|Maximum endurance||10 hours|
|Power||2 х 540 HP|